1. Field of the Invention
This invention relates to photohardenable compositions. More particularly, this invention relates to compositions which comprise an organic material having epoxide functionality and another organic material, compatible with the first organic material, which has a glass transition temperature in the range of -20.degree. C. to 105.degree. C. The compositions further contain an aromatic complex salt as photoinitiator and can be hardened by exposure to actinic radiation or electron beam irradiation.
2. Description of the Prior Art
Various types of plating and etching resists have been known and used for many years for various applications (e.g. in the making of printed circuitry, printing plates, etc.). Some types of resists are solvent-based and are hardened or solidified after being coated in the desired pattern by driving off the solvent (e.g. with heat). Some other types of resist are light sensitive and are hardened or solidifed by exposure to light after coating, whereupon the resist crosslinks or polymerizes to an insoluble state which is not easily removeable with conventional solvents.
In many applications it is extremely desirable (and in some cases it is necessary) to be able to rapidly and efficiently remove the resist pattern from a substrate with conventional solvent after the required etching or plating of the substrate has been completed. Although conventional solvent-based resists provide patterns which can later be removed with solvent after the desired plating or etching has been completed, such resists are undesirable by reason of the fact that in the initial formation of the resist pattern solvent must be removed. The pollution problems attendant with such procedure (i.e. removal of solvent), and the time required to obtain a hardened pattern, are inherent limitations associated with the use of such solvent-based resists.